Structural elucidation of a compound, whether a synthesis product or an extract from a natural source generally requires a number of analytical techniques. Infrared spectroscopy, mass spectrometry, and nuclear magnetic resonance (NMR) spectroscopy can provide extensive chemical information. NMR can provide structural information and also information on both intermolecular and intramolecular dynamics. Applications of NMR range from determination of three-dimensional structures of large proteins to the analysis of very small amounts of products from combinatorial syntheses. Furthermore, NMR is a nondestructive analytical method.
NMR probes typically have an inner coil for irradiation and detection of a first nuclear species, and a second larger coil coaxial with the inner coil for irradiation and or detection of one or more other nuclear species. The two coils can be oriented 90° with respect to each other to minimize coupling between the two coils. It should also be recognized that all of the inductors in the probe circuits should have minimal coupling (k<approximately 0.03) between them in order to reduce or eliminate cross talk between these elements unless the magnetic coupling is intended. Capacitive coupling has can be used to form multiply-tuned NMR probes for 1H-2H, 13C-15N and 1H-19F. Recently it has been shown by Zens in U.S. provisional patent application No. 62/148,137 entitled “NMR Analysis using a Dual Probe for HFC Measurements”, filed Apr. 15, 2015, that magnetic coupling can also be used to improve these multiple resonance circuits, which is explicitly incorporated by reference in its entirety.
The sample region can contain or all of the following: 1) multiple sample coils, 2) magnetic coupling loops, 3) coupling resonators, 4) variable tuning capacitors, 5) pulse field gradients, 6) Faraday shields, 7) loop gap shields and other components related to the performance and function of the probe that those skilled in the art of probe fabrication would recognize.